CH0302 Process Instrumentation

Department of Chemical Engineering School of Bioengineering SRM University Kattankulathur 603203

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Lecture 13 – Flow Measurements

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Introduction – Flow Measurements

Flow  Measurements    

Classifica<on  of  flow  measuring  instruments    

Various  configura<ons  for  flow  measurement    

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Flow  Measurement    

Introduction – Flow Measurements

•  The  measurement  of  flow  rate  and  flow  quan<ty  of  materials  is  made  primarily  for  the  purpose  of  determining  the  propor<ons  of  materials  introduced  in  the  manufacturing  process.  

•  Measurement  of  flow  rate  and  quan<ty  is  the  oldest  art  in  the  science  of  instrumenta<on  and  it  dates  back  to  great  hydraulic  and  public  works  of  romans      

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Classifica3on    

Introduction – Flow Measurements

Flow

 Meters    

Closed  channel  flow    

Orificemeter      

Venturimeter    

Rotameters  (or  Area  flow  meters)  

Open  Channel  flow    

Triangular  weir  or  V-­‐  notches    

Trapezoidal  weir  

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Configura3ons    

Introduction – Flow Measurements

Orifice  meter    

Bernoulli  principle    

Qtheo =a0 2.g.h

1− a0a1

⎛⎝⎜

⎞⎠⎟

2

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Configura3ons    

Introduction – Flow Measurements

Venturimeter    

Bernoulli  principle    Qactual =

a1a2 2gha12 − a22

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Configura3ons    

Introduction – Flow Measurements

Rotameters    

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Configura3ons    

Introduction – Flow Measurements

Velocity  distribu<ons  in  weirs    

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Configura3ons    

Introduction – Flow Measurements

V-­‐Notch  (Triangular  weir)    

Qtheoritical =815tanθ252g ×h

52

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Configura3ons    

Introduction – Flow Measurements

Trapezoidal  weir    

Qactual =23b 2h3

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Configura3ons    

Introduction – Flow Measurements

Flow  of  dry  materials    

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References

1.  Donald  P.  Eckman,  (2004)  Industrial  Instrumenta.on,  CBS  Publishers,  Pp.  1-­‐  27.  

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Thank You